Field of the Invention
The present invention relates to output of maintenance diagnosis information and a diagnostic-information display device, and more particularly, to a control device that outputs maintenance diagnosis information and a diagnosis-information recording/displaying device in which the maintenance diagnosis information can be output and displayed even when a CPU does not operate.
Description of the Related Art
As a method of displaying the operation condition or the failure condition of a control device at startup on a lamp or the like to offer the condition to users by showing a number or using an LED, a 7-segment LED display of a post (Power On Self Test) code on a personal computer has been widely known, for example.
The above method requires a display device dedicated for displaying the operation condition or the failure condition at startup. Since a 7-segment LED for maintenance or the like is usually unused, an extra cost is required. Further, since a 7-segment LED for maintenance is unused in a usual state, the 7-segment LED is set out of sight and it takes time to open a case or the like to check the 7-segment LED.
As a conventional technique for solving the above problems, a technique of outputting an operation condition using a general-purpose interface is disclosed (for example, Japanese Patent Laid-Open No. 2011-039684).
However, a general-purpose interface that is commonly used usually needs a complicated control circuit. Accordingly, such an interface cannot be used when the interface does not normally operate, when the initialization is uncompleted (for example, immediately after power is supplied), or when a CPU does not operate. Even in the technique disclosed in Japanese Patent Laid-Open No. 2011-039684, a CPU needs to operate in order to control the general-purpose interface although the operation condition can be output to the general-purpose interface. Accordingly, an operation condition or a failure condition at startup cannot be displayed when a CPU does not operate.